Small Scale Hydro
Small Scale Hydro
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| Djúpadalsvirkjun small hydropower plant is located in Eyjafjörður in North Iceland. |
Mannvit UK is an independent consultancy offering full-service engineering for small hydro development. From our office in Cambridge, Mannvit UK builds on over 40 years of experience in hydro development from our operations in Iceland.
Small Scale Hydro in the UK is growing. As a renewable energy source, hydro is reliable and increasingly more efficient with newer technology. Power from small hydro can earn revenue for project developers, and can play a role in compliance with Renewables Obligation legislation. Also, there are many suitable locations to develop small hydro in the UK, most commonly making use of old mill sites and weirs. It has been estimated that there are 260,000 locations where a hydropower turbine could produce electricity. (Source: Environment Agency, UK).
Mannvit UK Hydro Services:
- Hydropower engineering
- Civil Engineering
- Structural and mechanical design
- Power transmission
- Feasibility studies
- Site investigations
- Cost estimates
- Contract documents
- Bid evaluations
- Environmental impact assessments and reports
- Project management
- Project Planning
- On-site inspections
Engineering a suitable solution for small scale hydro installation includes determining technology and design that are well matched for the head, flow and other characteristics of an individual resource, the nature of the power demand, and land-use issues. In the past, hydro power technology favored larger sources of energy, higher head and volume. Now, newer designs have increased the system efficiency for smaller systems. Making the most of the potential energy in a location requires skillful execution of a variety of interrelated services and disciplines:
Environment:
Hydro solutions must be fish friendly, and flow characteristics should not adversely affect downstream areas. Mannvit services include environmental evaluations, monitoring and planning.
Power Delivery:
Power delivery includes both the transmission of power over high voltage transmission lines, and the supplier/customer purchase agreement for power consumption. Grid connections are needed to supply power beyond the immediate area, whether to execute contracts with green energy suppliers, and to supply the national grid. Power Purchase agreements (PPAs) are contracts stipulating the pricing, supply expectations and operational parameters for a power supplier / power consumer relationship. Power suppliers in a PPA can be for small scale hydro or a number of other power sources and power consumers can be public, power companies or private industry. Mannvit services include extensive experience in power transmission.
Financial Incentives and Compliance:
The financial driver for small hydro in the UK is the Feed in Tariff (FIT). With FITs, small hydro and other renewable energy projects become a much more attractive proposition and can be considered for their investment merit in addition to their benefits as an environmentally friendly energy source. FIT incentives have three primary components, and the tariffs for the primary component, generation, is set by a schedule according to the type of renewable energy, and the production capacity. The three components of FIT incentives are Power generation, Offset, and Export.
Power generation tariffs are paid to owners of a renewable energy source in direct proportion to the amount of power being generated.
Offsets are for energy used by the owners of the power source and are equivalent to simply not paying the market rate for the power generated. This is in addition to the tariff.
Export of power can earn additional income. Power that is generated above and beyond the need for on-site use can be exported back to the grid, earning additional revenue.
For a farm, business or other organization considering a renewable power generation scheme, FITs are an important component.
4 key components of a small hydro project
- An intake, incorporated into a weir, including trash and fish screens
- A penstock pipe to deliver the flow to the turbine, sized to minimise head loss
- A powerhouse for the turbine and generator
- An outflow to release water back to the river
Hydro technologies
There are 4 main types of hydro technologies used to generate electricity in small hydropower projects:
- Waterwheels which are robust and can be used for low head sites.
- Archimedes screw which are popular for low head sites, high efficiency and fish friendly.
- Impulse turbines, such as the Pelton, Turgo and Crossflow in which a high velocity jet strikes the plane of the runner at an angle.
- Reaction turbines; such as Propeller, Kaplan and Francis which use the oncoming flow to generate a lift force to propel the runner blades.